Melbourne:Players resorted to ice-packed vests, time-outs, or just gave up as searing heat baked courts and bodies and frayed nerves at the Australian Open on Tuesday. Organisers invoked the Extreme Heat Policy just after noon, clearing outside courts of players and closing the roofs of the two main stadiums. And officials defended rules requiring all matches already under way to be completed. Players said they suffered in the sweltering conditions - which soared past 38 degree celcius - but most were reluctant to criticise the policy or call for rules changes so that matches can be stopped for health reasons if it gets too hot. "My legs were very sore, my feet were burning ... it was pretty tough," said Camille Pin, who nearly upset top-seeded Maria Sharapova in almost three hours on center court before the Rod Laver Arena roof was closed. "But I think when we started the match it was the same conditions for both of us, so it's fair this way, and I think there's nothing to do about that," she said. Sharapova agreed, but thought the roof should have been closed during the match. "Definitely. We probably played an hour and a half, two hours in the conditions where the roof should have been closed," said the 19-year-old Russian, who took a medical time out because of the heat. "It's inhumanely possible to play three hours in that kind of heat. I don't think our bodies were made to do that." But she added, "A rule is a rule. Do I like it? Not necessarily, no." Tipsarevic worst affected Worst affected was Serbia's Janko Tipsarevic, who was two sets up and leading 5-2 in the third against eighth-seeded David Nalbandian when he went into meltdown. He donned a vest loaded with ice and repeatedly poured cold water over his head during breaks, but remained visibly wobbly and eventually gave up chasing shots before retiring in the third game of the fifth set. "I felt my heart pounding and then suddenly stop, then pounding, then stop. I felt like vomiting on the court. All that led to incredible exhaustion," Tipsarevic said. He said the heat was bad throughout the match but he wouldn't have wanted to stop while he was winning. "In this heat it is not tennis any more, it is who is going to stand longer in the sun," he said. Nalbandian, who made the semifinals here last year, said those who were not forced to play during the energy-sapping heat had an advantage later in the tournament, and the rule was unfair. "The thing I didn't understand is why they didn't call match after, I don't know, 40 degrees," he said. "The guys who are playing stay playing. Why didn't they stop all of it? But I don't know, that's the rules." Play was stopped on most courts less than two hours into play on Tuesday, delaying many of the 64 matches scheduled for the day by longer than six hours. Spectators need treatment More than 230 spectators were treated on Tuesday at the venue for conditions including dehydration, blisters caused by extreme sunburn, fainting and dizziness, said Paul Tempany, the senior officer for the St John Ambulance service that is providing first aid at the event. Four people were taken to hospital. Storms predicted for later on Tuesday had failed to arrive by sunset. And forecasters predicted hot temperatures for rest of the week. High temperatures are a regular feature of the Australian summer, filling beaches with people throughout the holiday season and fanning bushfires across the country's southeast. The so-called "Extreme Heat Policy," was introduced at the Australian Open in 1998 and has been refined twice since. It now relies on a complex calculation of "ambient air temperature, humidity and a measurement of the sun's intensity, combined with a sustained absolute temperature above 35 degree celcius." Tournament spokesman John Lindsay said the players had "shaped" the heat policy when it was introduced, and that many players had not wanted such a policy at all. "Andre Agassi was among those who saw the challenge of competing in the heat here as part of the challenge of winning the tournament," said Lindsay. "And it's important to note that those matches that continue on court after we've instituted the heat policy can be stopped at any time at the discretion of the tournament referee," added Lindsay. "If he determines that it's unsafe to continue because of medical advice or unsafe conditions, then the match would be stopped."